Fargier-Bochaton Odile, Wang Xinzhuo, Dipasquale Giovanna, Laouiti Mohamed, Kountouri Melpomeni, Gorobets Olena, Nguyen Nam P, Miralbell Raymond, Vinh-Hung Vincent
Radiation Oncology Department, Geneva University Hospitals, Geneva, Switzerland.
Radiation Oncology, Tianjin Union Medical Center, Tianjin, 300121, China.
Sci Rep. 2022 Jan 11;12(1):525. doi: 10.1038/s41598-021-04385-3.
Prone setup has been advocated to improve organ sparing in whole breast radiotherapy without impairing breast coverage. We evaluate the dosimetric advantage of prone setup for the right breast and look for predictors of the gain. Right breast cancer patients treated in 2010-2013 who had a dual supine and prone planning were retrospectively identified. A penalty score was computed from the mean absolute dose deviation to heart, lungs, breasts, and tumor bed for each patient's supine and prone plan. Dosimetric advantage of prone was assessed by the reduction of penalty score from supine to prone. The effect of patients' characteristics on the reduction of penalty was analyzed using robust linear regression. A total of 146 patients with right breast dual plans were identified. Prone compared to supine reduced the penalty score in 119 patients (81.5%). Lung doses were reduced by 70.8%, from 4.8 Gy supine to 1.4 Gy prone. Among patient's characteristics, the only significant predictors were the breast volumes, but no cutoff could identify when prone would be less advantageous than supine. Prone was associated with a dosimetric advantage in most patients. It sets a benchmark of achievable lung dose reduction.Trial registration: ClinicalTrials.gov NCT02237469, HUGProne, September 11, 2014, retrospectively registered.
俯卧位设置已被提倡用于全乳放疗中改善器官保护，同时不影响乳腺覆盖。我们评估俯卧位设置对右侧乳腺的剂量学优势，并寻找获益的预测因素。回顾性确定了2010 - 2013年接受治疗的右侧乳腺癌患者，这些患者同时有仰卧位和俯卧位计划。根据每位患者仰卧位和俯卧位计划中心脏、肺、乳腺和瘤床的平均绝对剂量偏差计算惩罚分数。俯卧位的剂量学优势通过从仰卧位到俯卧位惩罚分数的降低来评估。使用稳健线性回归分析患者特征对惩罚分数降低的影响。共确定了146例有右侧乳腺双计划的患者。与仰卧位相比，俯卧位使119例患者（81.5%）的惩罚分数降低。肺剂量从仰卧位的4.8 Gy降至俯卧位的1.4 Gy，降低了70.8%。在患者特征中，唯一显著的预测因素是乳腺体积，但没有临界值可以确定何时俯卧位比仰卧位更不利。俯卧位在大多数患者中具有剂量学优势。它设定了可实现的肺剂量降低的基准。试验注册：ClinicalTrials.gov NCT02237469，HUGProne，2014年9月11日，回顾性注册。
